I have figured out the problem: the installer removed nux-tools, left over from unity, but did not purge it. This left a start up script in /etc/X11/Xsession.d which interfered with gnome. Purged that and the problem was gone.
So this is a dependency bug in the nux-tools package (or perhaps some mistakenly identified changed file which turned into evil cruft). Sigh. Took me a long time to find this. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1768610 Title: No acceleration after upgrading to 18.04: gnome-session-check- accelerated incorrectly picks llvmpipe To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-session/+bug/1768610/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
